Methods for determining piezoelectric properties of thin epitaxial films: Theoretical foundations

L. N. McCartney*, L. Wright, M. G. Cain, J. Crain, G. J. Martyna, D. M. Newns

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

An analytical method is developed to determine piezoelectric properties of a thin film directly from measurements of bilayer deflection. As a significant extension to previous approaches, we include here the effects of bilayer bending, differential thermal expansion, and epitaxial lattice mismatch which commonly arise in practical measurements. The formulation reported here thus relaxes restrictive assumptions made in previous models thereby enabling a more direct link with experimental conditions. The model, which has been validated by comparison with finite element analysis, is shown to reduce to the well-known Lefki-Dormans result as a limiting case for thin films when bending and in-plane deformations are neglected. If the curvature of a simply supported bilayer can be measured, then the model offers a methodology for measuring the piezoelectric properties (epsilon(T)(33); d(31); d(33)), the film elastic constant s(11)(E) + s(12)(E), and lattice mismatch strains, provided a value of the elastic constant s(13)(E) can be determined or estimated. If curvature measurements are not available but lattice mismatch strains are known, then we find that it is still possible to measure these piezoelectric and elastic film properties.

Original languageEnglish
Article number014104
Number of pages13
JournalJournal of applied physics
Volume116
Issue number1
DOIs
Publication statusPublished - 7 Jul 2014

Keywords / Materials (for Non-textual outputs)

  • LASER INTERFEROMETER
  • SENSORS
  • SILICON
  • FERROELECTRICS
  • ACTUATORS
  • D(33)
  • COEFFICIENT
  • NANOSCALE
  • STRAINS
  • MEMS

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